Inner cover for annealing furnaces



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INNER COVER FOR ANNEALING FURNACES Filed Jan-1 16 1940 3 Sheets-Sheet 1-.

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w. A. BREEDON ETAL INNER COVER FOR ANNEALING FURNACES Filed Jan. 16, 1940 3 Sheets-Sheet 3 /1//AL 4, fleas-yam, Hora 4 fifiE/WAW 4/20 Patented Mar. 4, 1941 INNER, COVER FOR ANNEAIJNG FURNACES Will A. Breedon, Bratenahl, Floyd A. Garman,

Cleveland, and Frank W. Lorig, Lakewood, Ohio, assignors to The American Steel and Wire Company of New Jersey, a. corporation of New Jersey Application January 16, 1940, Serial No. 314,154

'1 Claim. This invention relates to inner or annealing covers as used for enclosing articles in annealingiurnaces, and particularly to an improved inner or annealing cover for use therewith.

5 It is now the general practice in annealing steel articles, as is well known to those skilled in the art, to enclose them in an inner or annealing cover in the annealing furnace to protect the surface of the articles being annealed from oxidation' or decarbonization and to protect the same directly from the intense heat therein, thereby obtaining a more uniform heating of the object or articles. Sometimes it is desirable to anneal the object or articles in a reducing atmosphere or otherwise suitably prepared atmosphere so as to prevent oxidation.

Various types of inner annealing cover; or boxes have been suggested and used but it has been found by experience that most of these covers become warped and very much distorted after a short period of use.

It is the usual practice in heatlng objects or articles in a reducing or otherwise suitably prepared atmosphere, to confine such atmosphere 25 within the airtight cover and seal the bottom 65 for the purpose of illustration and description,

edges thereof by disposing the same either in a liquid, sand, or other suitable sealing medium. It will be seen that such inner annealing covers 0 are subjected to a wide variation of temperatures within the furnace, thereby producing different elongations of the metal from which it is made which results in the warping and buckling thereof. Therefore, it is desirable that means be provided to compensate'for the different elongations to which the metal is subjected so as to prevent this undue distortion of such covers and it is to this that the present invention refers.

Accordingly, it is one of the objects of the present invention to provide an improved inner or annealing cover which is so constructed that it compensates for the different elongations and contractions of the portions of the cover, thereby preventing the distortion thereof. 1

It is another object of the invention to provide an improved inner or annealing coverwhich is simple and inexpensive in its construction, and

yet one which is strong and rugged and very effective in its use.

Various other obiects'and'advantages of this invention will becomemore apparent in the course of the following specification and will be particularly pointed out in the appended claim.

In the accompanying drawings, there is shown,

(or. 2634s) an embodiment and several modifications thereof which our invention may assume in practice.

In these drawings: Figure 1 is a plan of the improved inner cover of our invention;

5 Figure 2 is a cross sectional view through an annealing cover type furnace showing the inner cover of our invention incorporated therewith;

Figure 3 is an enlarged cross sectional view similar to Figure 2 through one sided the anhealing furnace as shown therein;

Figure 4 isa sectional view taken on line IV- IV of Figure 3;

Figures 5 and 6 are views similar to Figure 4 showing modified forms 01' expansion members which may be used in connection with the inner cover of the present invention; A Figure 7 is a view similar to Figure 3 showing a modified construction of the inner'cover of our invention:

Figure 8 is also a view similar to Figure 3 showing still another modified construction of our improved inner cover; and

Figure 9 is a fragmentary isometric view of the inner lower portion of the improved inner cover of our'inven-tion, showing one of the expansible members welded in place.

Referring more particularly to the. drawings, there is shown in Figure 1, an inner or annealing cover consisting of a rectangularly shaped base plate 2 having a. rectangularly shaped opening 8 arranged centrally thereof so as to provide apron-like portions 4 therearound. There is arranged around the outer edges of the base-like plate memberi a downwardly extending sealing member 5 which may be welded to the edge of the base plate or made an integral part thereof, whichever is desired, and adapted for a purpose to be described hereinafter. There is superimposed upon the base plate 2 enclosing the opening 3 therein an open-bottomed box-like light-weight metallic body member 6 having a top portion I, end walls 8 and side walls 9. The bottomedges of the end walls a and the side walls a are attached to the base plate 2 adjacent the edges of the opening 3 therein, preferably by means of welding. The side walls 9, as shown, are corrugated but it will be understood that these side walls may be straight, similarto the endwalls 8.

which are arranged at spaced apart intervals with each of the slots extending from the edge of the opening in the plate outwardly to a point intermediate the apron-like portions 4. There is also arranged in the side walls 8 of the box-like body member 8 a corresponding number of similarly positioned vertically extending slotted openings l2 which are arranged at spaced apart intervals directly opposite the slotted openings l openings l0 and i2, that is, over both the slot i0 in the base plate 2 and the slot l2 in the side.

walls 9, as is more clearly shown in Figure 9 of the drawings an irregularly shaped web or g flange-like member I3, preferably having substantially a U-shaped cross section with the free edges "thereof securely welded to the opposed edges of the slotted openings l0 formed in the base plate 2 and theslotted openings l2 formed in the side walls 9, thereby providing an airtight expansible Joint therebetween. That is to say, the lower edges of the side walls 9 of the body member 6 and the inner edges of the apronlike portions 4 of the base plate 2 are similarly cutaway at spaced apart intervals around the cover with a flange-like member 18 disposed over each of the cutaway portions and welded in place over such openings formed by the cutaway portions so aswto prevent the heat from escaping from inside the inner cover and to permit expension of the lower edges of the side walls 9,

together with the inner edges of the apron-like portions 4 of the base plate. It is preferable that the flange-like members l3 be angulariy shaped as shown in Figure 3, but it will be understood that these members may be of arcuate shape or any other suitable shape. Also, it is preferable that the flange-like members l3 have substantially a U-shaped cross'section as shown in Figures 4 and 5 of the drawings, or they may be'of any other suitable expansible cross section, such as V-shaped as shown in Figure 6. Thus, by providing such a construction, it will be seen that the lower inner edges of the side walls 9 of the body member 8 and the edges of the apron-like portions 4 around the opening 3 in the base plate 2 will be permitted to expand and contract similar to the action of an accordion during the heating and cooling thereof, thereby eliminating any tendency of the cover to distort or buckle.

Such an inner or annealing cover is adapted to be used with a furnace such as shown in Figure? of the drawings. This type of furnace has a base or hearth l4 on which the articles or object. to

around the outer edge of the base l4 and the shoulder portion is thereof a moat-like channel it in which there is disposed a liquid, sand, or other suitable sealing medium, in which the downwardly extending sealing members 5 of the inner cover are adapted to be positioned to seal the same from the atmosphere and to confine the reducing atmosphere therein. There is placed over the inner or annealing cover a conventional type outer or heating cover I! having downwardly extending side walls I8 which are adapted to rest preferably on blocks l9 disposed on top of the apron portion 4 of the base plate 2. 7

It will be seen that during the heat treating of the articles in the furnace, the inner edges of the'apron-like portion 4 of the base plate 2 ar .by the expansion members l3. It will also be seen that the shape 01 the expansion member i3 compensates for the difference in elongation or contraction of the inner edges of the apron-like.

portion 4 of the base plate 2 and the lower edges of the side walls 9 of the cover which are disposed in a. zone of variable temperatures as shown at 20 in Figure 3 of the drawings. In annealing covers as formerly constructed, the hottom edges of the side walls would buckle and tear away from the base plate, resulting in the escape of the prepared atmosphere from within the cover or permittingoutside air to enter thereinto and dilute the prepared atmosphere, thereby causing an increased cost of production or completely defeating the purpose of the annealing covers.- It will be seen that this trouble has been entirely eliminated in the cover of the present invention by providing spaced apart expansion joints therealong which automatically expand In Figure 7 there is shown a slight modiflcation of the compensating expansible means of the present invention. In this construction the side walls 9 are necessarily corrugated with thebottom edges thereof flared outwardly and terminating in corrugated arcuate shaped fillet-like portions 2i which, in turn, terminate in flat horizontal apron-like portions 22. It will be seen that, likewise in this construction, the difference in elongation between the side walls 8 and the apron-like portions 22 will be compensated for by the expansible corrugated arcuate shaped filletlike portions 2|.

There is shown in Figure 8 of the drawings another modification of the present invention. In this construction the side walls 9 of the inner cover are again corrugated with the corrugated side walls flared outwardly at the bottom thereof so as to provide corrugatedarcuate shaped filletlike portions 23 which terminate in corrugated apron-like horizontal portions 24. Thus, it will also be seen in this construction that the diii'erence in elongation between the side walls I of the mar cover and the apron-like portions 24 will be compensated 'for by the corrugated arcuateshaped fillet-like portions 23. In the latter construction, there is preferably disposed in the corrugatlons below the blocks IQ adjacent the outer edges of the apron-like portions 24 and there- ,under supporting blocks is which are adapted prevent the welded Joints thereoi' from breaking.

While we have shown and described an embodiment and several modifications of our invention, it will be understood that these embodiments are merely for the purpose of illustration and description and that various other forms may be devised within the scope of the invention, as defined in the appended claim.

We claim:

An inner cover for use in enclosing articles in an annealing furnace comprising a metallic base plate having substantially a rectangular opening centrally arranged therein so as to provide an apron-like portion therearound, an open-bottomed light-weight substantially rectangular shaped hood superimposed on saidbase plate over said opening therein'having its lower edges securely welded to the inner edges 01! the rectangular opening in said base plate, said hood having end walls, a top wall and continuously corrugated side walls, said base plate having a plurality of slots arranged thereinv at spaced apart intervals along the sides of said hood extending from the inner edges or the rectangular opening therein outwardly to a point intermediate the sidewalls thereof, and an expansible web member having substantially a U-shaped cross section disposed over each or both the slots in the apron-like portionsoi' the base plate and said side wall of the hood with the edges of the web member securely welded to the edges of both the slots in the base plate and the slot in the side wall of the hood thereby enclosing both of said slots by a common means so as to provide an expansible inner joined edge between the base plate and the hood, thus permitting the inner part oi the apron-like portions and the side walls of the hood to freely expand and contract relative to the outer part of the apron-like portions without distortion of the cover.

WILL A. BREEDON. FLOYD A. GARMAN. FRANK W. LORIG. 

